Guard for machinery.



W. J. PARKINSON. GUARD FOR MACHINERY. APPLICATION FILED SEPT. 18, 1912.

Patenm 11.20, 1914.

stratr zs WILLIAM J. ramrrnson, or B-QGH-ES IEB, unwyonn, assrc voa rorarronann- STAMPING COMPANY, or nocnns'rna; navy roan, A GQBPQBA'EIONor. new

YORK.

GUARD FOR MACHINERY.

Specification of Letters Patent.

Patented Jan. 20, 1914.

7 '0 all whom it may concern:

Be it known that I, WILLI M J. PARKIN- SON, a citizen of the UnitedStates, and resident of Rochester, in the county of Monr e a d tate ofNew or ha in certain new and useful Improvements in Guards forMachinery, of which the followh1g1 is a specification;

his invention relates to guards, such as are employed in connection withpresses and other machines, to revent injury to the hand of an operatorthrough accidental contact with the operating-instrumentalities ormoving parts of such machines. In guards of thek'ind in question,especially as used in connection with presses, t has been common toemploy a guard-member which is normally out of operative position, so asto afford unobstructed access to the dies or other instrumentalitiesofthe machine, but which is so connected with the mechanism by which themachine is started and stopped as to be moved into operative positionjust before, or at the same time that, the machine is thrown intooperation by means of u treadle or other manually-operable member. The ps nt invention rela to guard of this type, and the ob'ect of theinvention 7 is to produce a guard 0' simple construction an re iable opn, an Pa i ular y to so arrange the mechanism by which the uard isactuated and the machine is controlled that the uard may be moved fullyto operative posi ion before any movement is imparted to the clutch orother device by which the machine is thrown into operation, thus void ngth anger f op ra i mo ment of the machinebefore the guard has been broht lnto a osition in which it will absolu ely prevent the operatorshands from being engaged by the'moving parts of the miwhine.

To the foregoing end the invention consists in the guard hereinafterdescribed, asit is efined in the succeeding claims.

11 the ac omp ny ng drawings igur 1 is a side-elevation of a pressrovide with a guard constructed in accor ance with the presentinvention; Fig. 2 is a rearrelevation, on a larger scale, of a portionof the guard-mechanism including the three rockne memw e; Fis- 3 is a camedian -we 0f t me dow in e 2; fig 4, ,5 one B are sideelevations. camelr 1 section, on the line X-X in Fig. 3, showing diflerentoperativepositions of the guardmechanism.

The invention is illustrated as applied to a press of ordinary form,such as is employed in InctaLpunching and stamping operations, this resshaving the usual vertically-movable head 1 and actuatingmechanismtherefor including a drive-shaft This drive-shaft is thrown into and outof operation in the usual manner, by aclutch which may be of anyordinary or suitable form, and is not, therefore, illustrated. Thisclutch is thrown into and out of operation in the usual manner,by meansof mechanism including a bell-crank lever 3 ivoted on the frame 7 of themachine, this liver being rocked clockwise, or to the right, from theillustrated position in order to throw the clutch into operation. Thepress is also provided in the usual manner with a manuallyoperablemember. in the form of a treadle 4. which is depressed by the operatorfor the purpose of l'ln'owin the drivingmcchanisln into operation. histreadle is carried by a lever 5, which is pivoted to the frame at 6 andis held normally in raised position by a spring 38. The guard-propercomprises a horizontal bar 8 which extends transversely in front oi thehead 1.. This bar is mounted in a lug 9 ad'ustably fixed upon a lever10, which cxtcn s rearwardly and is arranged to swing about whorizontalstud ll projectin from the frame 7. When the machine at rest theguard-bar 8 is held in raised position, the lever 10 beiu provided witha counterweight 12 for th s purpose and being arrested in normalposition by a sto -screw 13 threaded into 1). lug projecting iion theframe 7.

' In order to guard the hand of the operator from accidental engagementwith the dies when the press is in operation it is necessary that thelever ll) be swung downwardly and the guard ha" 8 brought to the levelof the table .26 ot the press before the clutch is operated to start theuu'vvmncul, of the n'css. and for this rmrposc the guard "mechanism isassociated with the connections between the treadlelever 5 and thebell-crank lever 3 through which the clutch is actuated. Theconstruction by which thisis oocouiplished is shown partlcularly in Fgs. 2-6. The lever 10 is fixed in an arm consiituiiun a lever 3. g a j ISince the rocking-memberlG, through its connection with the treadle,constitutes part of'a roclringme'mber 14 journaled upon the stud 11. Therocking-member 14 is provided with a cylindrical hub or sleeve 15 -whichconstitutes a journal and support for another rocking-member 16.Themember 16 is also provided with an arm, to which is pivoted the upperend of a rod 1'7 connected, at its lower end, with the treadle-lever 5,sothat when the treadle is depressed the member 16 is rocked about thesleeve 15.

A washer 18 on the stud holds the members 14 and 16 against endwisemovement there from. Still another rocking-member 19 is journaled on thestud, and has an arm WlllCh is connected, by a rod 20, withthebell-crank means by whichboth the guard-proper and the clutch areactuated, and since it is desirable that the guard be brought fully.into operative position before any movement is imparted to the clutch,it is necessary that after the guard has been so brought down the-member16 may be further actuated, by continued movement of the treadle, tooperate the clutch, while the guard remains in stationary position.Accordingly, yielding connections are employed between the guard and therocking-member 16, to permit independent movement of the latter. A post21 projecting from the member 16, and a pin bar 8 rests upon the top ofthe table 26, as

shown in Fig. 5. During this time the rocking-member 19 remainsstationary, no movement .being. imparted to the clutch. In order thatthe clutch may be thrown into operation} at the proper time, however, alug .27 projects from the rocking-member 19 in a position in which itmay be engaged by the inner extremity of the lug 24 when the member- 16has moved from the normal position of Fig. 4 to the position of Fig. 5.Accord-V ingly, after the guard has been depressed as just described thecontinued downward movement. of the treadle, through the engagement ofthe lugs 24 and 27, causes the member 19 to rock, thus pullingdownwardly the rod 20 and swinging the bell-crank lever '3 so as toactuate the clutch and throw the driving-mechanism into operation.During this later part of the movement of the treadle the guard-properand the member osses? 14 remain stationary, and the spring 23 yields topermit the. continued movement of the member 16. i i i It is importantthat in case the operators hand be in position to be engaged by theguard in its descent the operation of the clutch be positively preventeduntil the-hand has been withdrawn from such position. Accordingly, meansare provided for posi-, tively interconnecting the members 16 and 14under such circumstances, to interrupt the movement of the member 16until the guard has been permitted to descend fully to operativeposition. For this purpose the. member 14 is provided with a lug 28having an adjustable stop-screw 29 which is ada p'ted to engage theupper surface of the lug 24. The stop-screw is so adjusted that in thenormal operation of the mechanism, when the guard has descended fully tooperative position, the screw is not engaged by the lug 24 until themember 16 has been rocked throughout its entire range of movement andthe clutch has been thrown into operation. As shown in Fig. 5, forexample, it will be apparent that when the guard is in depressedposition there is sufiicient space between the screw 29 and the lug .24to permit further movement of the member 16,

and, as the lugs 24 and 27 are at this time case before the lug 27 andthe member 19 have been moved far enough to throw the clutch intooperation. The member 16 being thus arrested positively, the machinecannot be started until the operators hand has been withdrawn so as topermit the guard to descend fully.

In order that the operator may be pre vented from introducing his handto a position of danger after the guard has descended, a screen or plate30 is preferably fixed to the bar 8 so as to project upwardly therefromand close the entire space between the table 26 and the head 1 of thepress. The arrangement of the rocking-members 14 and 16 by which thelatter is journaled upon the former, as described, not only renders themechanism compact and rigid, but also reduces the friction of itsoperation, since the members 14 and 16 turn as one during the -movementis imparted to the clutch 'to throw the drivingmechanism into oporation.In guards previously employed this has not been the case, but movementhas been imparted simultaneously to the clutch and to I the guard duringthe whole or a portion of the operative movement of the guard. Such anarrangement is, however, unreliable owing to the fact that the guarddoes not fully reach its operative position before movement is impartedto the clutch, so that as the result of wear upon the parts of theclutch-mechanism the clutch is liable to become operative before thefull movement of the controlling-mechanism originally provided for, and,accordingly, guards constructed as just described do not constitutecomplete safeguards against the presence of the operators hand at thepoint of danger when the machine begins to operate.

-My invention is not limited to the embodiment thereof hereinbeforedescribed and illustrated in the accompanying drawings, but may beembodied in various other forms within the nature of the invention as itis defined in the following claims.

I claim a 1. In combination with a press having a driving-clutch and atreadle; a first rockingmember having a bearing on a fixed part of themachine and connected with the treadle; a second rocking-memberjournaled coaxially with the first and connected with the clutch: athird rocking-member journaled coaxially with the first and second andcar rying a guard adapted to swing into position in front of theoperative instrumentalities oft-he ress; a spring connecting the firstand third rocking-members to swing the guard into operative positionduring the first part of the movement of the treadle; cooperatingabutments on the first and third rocking-meinbers. normally separated toprovide lost-motion,but adapted to move the guard positively tooperative position during the later part of the movement of the treadle;cooperating abutments on the first and second rocking-members normallyseparated to provide lost-motion but adapted to move the secondrocking-member and throw the clutch into operation during the later partof the movement of the treadle; and means for raising the guard out ofoperative position when the treadle is in normal position and the clutchdisengaged.

2. In combination with a press having a driving-clutch and a treadle; afirst rocking member having a bearing on a fixed part of the machine andconnected with the treadle; a second rocking-member journaled coaxiallywith the first and connected with the clutch; a third rocking-memberjournaled coaxially with the first and second and carrying a guardadapted to swing into position in front of the operativeinstrumentalities of the press; a spring connecting the first and thirdrocking-members to swlng the guard into operative position during thefirst part of the movement of the tread e; cooperating abutments on thefirst and third rockingmembers, normally separated to providelostmotion, but adapted to move the guard positively to operativeposition during the later part bf the movement of the treadle;co6pcrating abutments on the first and second rocking-members, normallyseparated to provide lost-motion, but adapted to move the secondrocking-member and throw the clutch into operation during the later partof the movement of the treadle; means for raising the guard out ofoperative position when the treadle is in normal position and the clutchdisengaged; and a stud fixed in the frame and upon which the second andthird rocking-members are mounted directly, the first rocking-memberbeing mounted, and having a bearing, upon the third rockingmemberconcentric with the stud.

WILLIAM J. PARKINSON.

Witnesses D. Gunners, L. THON.

Copies 0! this patent may be obtained for flve cents each, by addressingthe Commissioner of PatentI,- Washington, D. C.

